1. Field of the Invention
This invention relates to a new and improved method of inhibiting premature budding of a short-day floral crop and, in particular, to a new and improved method of inhibiting premature budding and subsequent flowering of such a crop. Accordingly, it is a general object of this invention to provide new and improved methods of such character.
2. Description of the Prior Art
Commercially, chrysanthemums and other short-day flowering crops are prevented from flowering during short days by the use of low intensity (40 .mu.W/cm.sup.2 -80 .mu.W/cm.sup.2) incandescent light given as night-interruption for four hours. Some growers have also used cyclical lighting for five minutes every half hour through the fifteen hour dark period as an energy conservartion measure.
As reported by Elwood D. Bickford and Stuart Dunn in "Lighting for Plant Growth", 1972, long day responses for both short-day and long-day plants are usually accomplished by continuous lighting for a period of four to eight hours before sunrise or after sunset (photoperiod extension), continuous lighting for a two to five hour period in the middle of the dark period ("night break"), or interrupted lighting for a two to five hour period in the middle (10 p.m. to 2 a.m.) of the dark period (cyclic- or flash-lighting). In the latter method of lighting, incandescent lamps are cycled, or flashed, on for 2 to 7% of a time period, i.e., one to four seconds during each minute or one to four minutes each hour, etc.
The premature flower buds formation in chrysanthemum cultivars is a total loss to the grower. Present commercial approaches for inhibiting flower bud initiation require long exposure to night-lighting with incandescent lights, and therefore, are energy consuming and economically unfeasible. Some commercial growers of field chrysanthemums use one hundred 150 watts reflectorized incandescent lamps per acre which are turned on 21/2 to 3 hours per night, depending on the season (longer during the winter months). The lights are used every night from mid-August to mid-March for control of harvest time (achieved by flower inhibition). The energy expense is considerable. When the lights are on, the plants do not flower; the grower can turn out the lights in selected areas for flowering to occur on "cue". As a result, flowers can be picked for the Eastern U.S. cut flower industry on a timely and controlled schedule from August to March. However, the cyclical lighting approach that has been used commercially has generally been abandoned by growers due to timing clock failures and the like.